Swift's rep, Tree Paine, tells PerezHilton.com:
Wow. Wow. Wow.
Kanye is straight-up INSANE!!!!!
A refreshing twist on an old school favorite!
And girl surprised the crowd with the first ever performance of her unique take on Backstreet Boys classic, I Want It That Way!
Open your ears to Charli's killer cover (above)!
Ahhhh we LOVE LOVE LOVE when artists cover songs but manage to make them completely their own!
And as fun as the original BB tune is, we are definitely digging Charli XCX's slower, softer edition.
SO many hearts!